Method Of Making An Alkoxylated Polyethylenimine Product

ABSTRACT

A method of making an alkoxylated polyethyleneimine (APEI) product having reduced discoloration includes treating a composition including a component selected from the group of polyethyleneimine (PEI), alkoxylated polyethyleneimine (APEI) intermediate, and combinations thereof that is used to make the APEI product. The method of treating the composition includes adding water to the composition in an amount of from 2 to 20 parts by weight, based on the total weight of the composition. The water is stripped from the composition within a relatively low temperature range of from 158 to 203° F. until less than or equal to 0.2 parts by weight of water, based on the total weight of the composition, is present in the composition. The aqueous solutions of APEI product thus made have Gardner color values of less than 6.

RELATED APPLICATIONS

This patent application claims priority to and all advantages of U.S.Provisional Patent Application Nos. 60/650,990 and 60/650,914 which,were filed on Feb. 8, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to a method of making an alkoxylatedpolyethyleneimine product. More specifically, the subject inventionrelates to a method of treating a composition including a componentselected from the group of polyethyleneimine, an alkoxylatedpolyethyleneimine intermediate, and combinations thereof to improve theappearance of the alkoxylated polyethyleneimine product in an aqueoussolution.

2. Description of the Related Art

Alkoxylated polyethylenimines (APEIs) are known in the art, as aremethods of making APEI products including the APEIs. Among the APEIs,propoxylated polyethylenimines (PPEIs) and ethoxylated polyethylenimines(EPEIs) are most common in commercial applications. The EPEIs arecommonly used in consumer products, especially laundry detergents, andgenerally function as dispersants by chelating cationic particles, suchas clay particles, and holding them in solution. The EPEIs hold theparticles in suspension until the particles are removed through arinsing process, thus preventing the particles from re-depositing on thefabric in the laundry.

Current methods of making the APEI products start from a compositionincluding polyethyleneimines (PEIs). A method of making the compositionincluding the PEIs is by reacting ethylenediamine (EDA) and ethylenimine(EI) under acid catalysis, in solvents such as water. An example of acommon EI is aziridine, which is a three-member ring having a reactivenitrogen. The EI is polymerized through a ring-opening reactioninvolving the reactive nitrogen of the aziridine. The reaction ismaintained until the amount of unreacted EI falls below a predeterminedlevel. The resulting polyethylenimines (PEIs) in the composition haveprimary, secondary, and tertiary amine functionalities that areavailable for further chemical conversion, e.g. alkoxylation withalkylene oxides such as ethylene oxide to form APEI. The ethoxylation ofPEIs is described in Houben-Weyl, Methoden der organischen Chemie, 4.Ed., Vol. 14/2, p. 440 ff. (1963) and Vol. E 20, p. 1367 f. (1987).

One of the problems with current APEI products is discoloration inaqueous solutions including the APEI products. Incorporation of APEIproducts that cause significant discoloration in consumer products isundesirable since it can distort the desired color and appearance of theconsumer products, which in turn can diminish consumer appeal. Thediscoloration of the aqueous solutions including the APEI products istypically measured using a UV-VIS spectrophotometer or by comparing theaqueous solutions including the APEI products to color standards such asGardner color standards. In such measurements, the APEI products arediluted with solvents like water or alcohols, e.g. methanol or ethanol,THF, DMF or aqueous acids, to concentrations that are practical todetermine coloristic properties. These concentrations can range from 5to 30% by weight for the active polymer. Measurements of the coloristicproperties are conducted at various wavelengths that can range from 350to 800 nm and are carried out in one or two channelUV/Vis-spectrophotometers.

It is known in the art that impurities present in compositions includingthe PEI produce significant discoloration and high color in the aqueoussolutions of APEI product made from them. However, there is no way ofknowing from the appearance of the composition including the PEI whetheraqueous solutions of APEI product with sufficiently low color can bemade, since the compositions including the PEI are generally of lowcolor, in the range of 1 to 3 by the Gardner standard.

Hydrides, such as sodium or potassium borohydride, are thought toimprove the color of the aqueous solutions of APEI product and are oftenused in the manufacturing process. The aqueous solutions of APEI productmanufactured following the conventional processes are highly colored andthe formation of color bodies is unpredictable. For the aqueoussolutions of APEI product manufactured following the conventionalprocesses, Gardner color values are typically above 10 and often in therange of 14-18. Aqueous solutions of APEI product having Gardner colorvalues greater than 10 are considered significantly discolored, andtheir utility in consumer products is inhibited. It is desirable toobtain aqueous solutions of APEI product with Gardner color values lessthan 6, which are presently unattainable through the use of the hydrideor other measures alone.

U.S. Pat. No. 6,451,961 to Suzuki et al. suggests a method of treatingcompositions including PEI that have been produced from EI, which inturn was manufactured via a dehydration reaction of monoethanolamine inthe presence of a catalyst. The method includes adding water to the PEIin an amount of from 1 to 95 parts water, based on the weight of the PEIto form the composition including the PEI. At least 15 percent of theadded water is then distilled out of the composition at a temperature offrom 212 to 392° F. and at reduced pressure to remove volatileimpurities such as excess ethanolamine and other low-boiling residualcomponents such as ammonia, lower alkyl amines, and aldehydes. Accordingto the '961 patent, those volatile impurities cause offensive smell anda reduction in stability of the polyethyleneimines when present.

While it is obvious that water and other volatile compounds that are notchemically bound to the PEIs will be more quickly removed from thecomposition at higher temperatures, there could be factors that controlthe outcome of alkoxylation of the PEIs other than the removal ofvolatile impurities. Specific factors that may control the outcome ofalkoxylation include the reaction of products of carbonyl compounds withthe nitrogen functionality of the PEIs, subsequent removal of thoseproducts through distillation, and possible structural changes of thePEIs due to the removal of cross-linking building blocks. Such factorsare not accounted for by the treatment method of the '961 patent.Furthermore, ethanolamine and ammonia, which are removed in thetreatment method of the '961 patent, are not considered harmful in thesense of causing discoloration. More specifically, the functionalitiesof the ethanolamine and ammonia are also found in compositions includingthe PEI and/or the APEI product. Ethanolamine and ammonia are known toreadily participate in the alkoxylation process, leading to colorlessAPEI products. Hence many of the impurities removed in the '961 patentneed not be removed to reduce discoloration of the aqueous solutions ofAPEI product, and the drawbacks of the presence of the ethanolamine andammonia are not experienced by the consumer since the ethanolamine andammonia are consumed during the production of the APEI product, thusyielding minute amounts of high molecular weight products in the APEIproduct that are chemically similar to the APEI. Finally, the presenceof water in the composition including the PEI negatively affectsalkoxylation beyond the reaction of one equivalent mole of alkyleneoxide for each functionality of the PEI. As a result, the presence ofexcessive quantities of water during alkoxylation to produce the APEIproduct, which has more than one moles of alkylene oxide for eachfunctionality of the PEI, is undesirable.

There remains an opportunity to provide a method of making APEI productsthat consistently exhibit improved color properties in aqueous solutionsof the APEI products, namely Gardner color values of less than 6,without affecting the chemical structure or properties of the APEIproducts.

SUMMARY OF THE INVENTION AND ADVANTAGES

The subject invention provides a method of treating a composition and amethod of making an alkoxylated polyethyleneimine (APEI) product. Thecomposition includes impurities. The composition also includes acomponent selected from the group of polyethyleneimine (PEI),alkoxylated polyethyleneimine (APEI) intermediate, and combinationsthereof. The method of treating the composition includes the step ofadding water to the composition. The water and at least a portion of theimpurities are stripped from the composition at a temperature of from158 to 203° F. until less than or equal to 0.2 parts by weight of water,based on the total weight of the composition, is present in thecomposition. The method of making the APEI product further includes thestep of alkoxylating the component in the composition to make the APEIproduct.

By stripping the water and the impurities from the composition withinthe temperature range of from 158 to 203° F., and by stripping untilless than 0.2 parts by weight water, based on the total weight of thecomposition, is present in the composition, a sufficient amount ofcertain impurities that cause high discoloration in the APEI productsare removed from the composition to improve color properties in the APEIproducts made from the composition, while retaining other impurities inthe composition that are not harmful in the sense of causingdiscoloration. Furthermore, the impurities are removed without causingstructural changes in the PEI and/or APEI intermediate in thecomposition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of one method of making the alkoxylatedpolyethyleneimine product of the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Referring to FIG. 1, a method of making an alkoxylated polyethyleneimine(APEI) product may include the step of making a composition includingpolyethyleneimine (PEI). The PEI is made by starting with a di- orpolyamine such as ethylene diamine (EDA), ethylenimine (EI) such asaziridine, water, and an acid catalyst. Acid catalysts such as sulfuricacid, carbonic acid, or any lower carboxylic acid catalyst, e.g., C1 toC6, may be used for the production of the composition including the PEI.Specific examples of suitable acid catalysts include sulfuric, formic,and carbonic acids. The PEIs in the composition are available at a rangeof molecular weights and have a number average molecular weight of atleast 150, more preferably from 600 to 30,000. An example of acomposition including PEI that is one formed from carbon dioxidecatalysis, in the presence of water, in which the PEI has a numberaverage molecular weight of about 600.

The catalysts used to make the PEI in the composition form adducts withthe PEI. As is known in the art, conjugate bases, i.e., sulfate,formate, or carbonate ions, depending on which catalyst is used, and theadducts those bases form with the PEI, exhibit different chemicalcharacteristics when those adducts are further processed.

The resulting PEI in the composition has primary and secondary tertiaryamine functionalities that are available for further alkoxylation withalkylene oxides, such as ethylene oxide or propylene oxide, to make APEIproducts such as ethoxylated polyethyleneimines (EPEIs), propoxylatedpolyethylenimines (PPEIs), respectively. The ethoxylation of PEIs isdescribed in Houben-Weyl, Methoden der organischen Chemie, 4. Ed., Vol.14/2, p. 440 ff. (1963) and Vol. E 20, p. 1367 f. (1987), both of whichare hereby incorporated by reference.

A ratio of primary, secondary and tertiary amine functionalities in thePEI can be determined via an established NMR-methodology. Table 1summarizes data from recent analyses of PEI made under acid catalysisand having a number average molecular weight of about 600:

TABLE 1 Primary amine Secondary amine Tertiary amine Samplefunctionalities functionalities functionalities PEI, M_(n) = 600 49% oftotal 25% of total 26% of total amine groups amine groups amine groups(13.3 g/100 g) (6.8 g/100 g) (7.2 g/100 g)

The determination of water content of the composition including the PEIis important because the composition including a component selected fromthe group of PEI, APEI intermediate, and combinations thereof issubjected to a method of treating by adding more water to removeimpurities in the composition that cause discoloration of the APEIproduct made from the composition. The composition may be treated at anytime prior to alkoxylation to make the APEI product under catalysisother than by water. For example, the composition including thecomponent selected from the group of PEI, APEI intermediate, andcombinations thereof may be treated at the site of production of thecomposition or at the site of alkoxylation of the PEI in thecomposition. Resulting aqueous solutions of the APEI product exhibithigh transmission, i.e., reduced discoloration.

In one embodiment, the method of treating the composition includesadding water to the composition including the PEI. The water may beadded to the composition including the PEI in an amount of from 2 to 20parts by weight, based on the total weight of the composition.Alternatively, the composition may already include water in the amountof from 2 to 20 parts by weight such that additional water need not beadded. The composition including the PEI and water is heated to arelatively low temperature of from 158 to 203° F. It is to beappreciated, however, that the water may be added to the compositionincluding the PEI after the composition has been heated into the abovetemperature range. Additionally, the composition including the PEI andwater is typically subjected to a pressure of from 0.1 to 250 mm Hg toeffectively create a vacuum. It is desirable to achieve a low watercontent in the composition including the PEI. As such, the water and atleast a portion of the impurities are stripped from the composition bymaintaining the composition within the above temperature and pressureranges until the less than or equal to 0.2 parts by weight, typicallyless than or equal to 0.1 parts by weight of water, based on the totalweight of the composition, is present in the composition. Anon-condensable gas sparge may also be used, and the compositionincluding the PEI and water may be subjected to agitation to aid instripping the water from the composition. The non-condensable gas may beselected from the group of, but is not limited to, nitrogen, argon, andcombinations thereof. Stripping water can remove at least a portion ofthe impurities that, during the alkoxylation of the PEI in thecomposition, will lead to highly colored aqueous solutions of the APEIproduct. The step of stripping the water from the compositionconcomitantly removes at least a portion of the impurities that causediscoloration.

The stripping step may take up to 40 hours depending on the initialamount of water added to the composition including the PEI, thepressure, and the use of the sparge by a non-condensable gas.

It was found that the main cause leading to discoloration of the aqueoussolutions of the APEI product is linked to the impurities in thecomposition including the PEI. Although it was hypothesized in the priorart that aldehydes were the main cause of discoloration, experimentationdisproved the link between aldehydes and discoloration of the aqueoussolutions of the APEI product. The addition of water to the compositionincluding the PEI, coupled with stripping the water and at least aportion of the impurities from the composition at the relatively lowtemperature of from 158 to 203° F. and pressure of from 0.1 to 250 mmHg, removes at least a portion of the impurities in the composition thatare most problematic in terms of causing discoloration, while typicallyretaining at least a portion of select impurities in the compositionthat do not cause discoloration of the aqueous solutions of the APEIproduct. Such select impurities include ethanolamine and ammonia, whichparticipate in alkoxylation of the PEI in the composition and containfunctionalities that are also present in the PEI or the APEI product.Furthermore, the relatively low temperature ensures that more PEI willbe retained in the composition, as compared to prior art processes thatuse higher temperatures for removing the impurities. As a result oftreating the composition, aqueous solutions of APEI product made fromthe composition that has been thus treated are visually considerablylighter and have Gardner color values, as measured in accordance withASTM D 1544-04, of less than 6, typically from 2 to 4. Similar Gardnercolor values are also achieved through another method, specifically amethod of treating a composition including an adduct of a conjugate baseand polyethyleneimine, a component selected from the group ofpolyethyleneimine, alkoxylated polyethyleneimine intermediate, andcombinations thereof, and, optionally, water, as set forth in PCTApplication No. ______ entitled “Method of Making an AlkoxylatedPolyethyleneimine”, and filed on even date herewith, the disclosure ofwhich is hereby incorporated by reference in its entirety.

In one embodiment, the composition including the PEI and the APEIproduct may be made at the same facility. Due to spatial constraints andthe shear volume of APEI product produced from the composition includingthe PEI, the composition including the PEI may be produced at onefacility and shipped to other facilities, where logistics may allow formore efficient delivery of the APEI product. Alternatively, PEI may bepartially alkoxylated with alkylene oxide, in an amount less than a fullcharge of the alkylene oxide required to make the APEI product, to formthe composition including the APEI intermediate to cut down onproduction inefficiencies. Typically, the APEI intermediate has about 1alkylene oxide molecule for each functionality of the PEI.

In another embodiment of the present invention, the compositionincluding the APEI intermediate is subjected to the method of treatingthe composition. Typically, the composition is treated prior to theaddition of hydroxide and subsequent alkoxylation to make the APEIproduct. More specifically, water is added to the composition includingthe APEI intermediate and stripped from the composition at thetemperature of from 158 to 203° F. until less than or equal to 0.2 partsby weight of water, typically less than or equal to 0.1 parts by weightof water, based on the total weight of the composition including theAPEI intermediate, is present in the composition.

The presence of water, after the composition including the APEIintermediate is formed from the PEI, is undesirable because sidereactions take place between the water and the additional alkylene oxidethat is added to the composition including the APEI intermediate to makethe APEI product. Thus, any water that is added to the composition mustbe stripped at some time before the composition including the APEIintermediate is alkoxylated to make the APEI product under basecatalysis in order to avoid formation of unwanted impurities, such aspolyethylene glycol.

A typical PEI used in the method of the present invention has an averagefunctionality of about 14. That is, on average, 14 functional groups(N—H functionalities) are present on each PEI molecule. To form the APEIproduct by way of the composition including the APEI intermediate, thePEI is partially alkoxylated with only a portion of the total alkyleneoxide to be used, thus resulting in the composition including the APEIintermediate. Then, the APEI intermediate in the composition isalkoxylated with the rest of the alkylene oxide under base catalysis toeffectively form the APEI product. To form the APEI product, the PEI orAPEI intermediate in the composition is alkoxylated with a total of from5 to 40 alkylene oxide molecules for each functionality of the PEI.Preferably, the PEI or APEI intermediate in the composition isalkoxylated with from 10 to 30, more preferably about 20, alkylene oxidemolecules for each functionality of the PEI, to make the APEI product.Since the PEI has about 14 functionalities, the APEI product has from 70to 560 moles of alkylene oxide for each mole of PEI.

A borohydride may be added to the composition including the componentselected from the group of the PEI, the APEI intermediate andcombinations thereof. The borohydride may be selected from the group ofpotassium borohydride (KBH₄), sodium borohydride, and combinationsthereof. Typically, the borohydride is added before alkoxylating the PEIin the composition to form the APEI intermediate or APEI product. Theborohydride is typically present in an amount of from 0.05 to 0.5 partsby weight based on the total weight of the composition and reducesaldehydes or other undesirable compounds still present in thecomposition. A hydroxide selected from the group of potassium hydroxide,sodium hydroxide, and combinations thereof may also be added to thecomposition at this point to catalyze the alkoxylation of the PEI withthe alkylene oxide, provided that the PEI is first subjected to theabove method of treatment. The composition including the KBH₄ is thenheated to a temperature of from 160 to 200° F. for up to one hour, wateris added, and alkylene oxide is charged at higher temperatures asdescribed in Houben-Weyl.

The following examples illustrate compositions and Gardner color valuesthat may be obtained for aqueous solutions of APEI product producedusing various components and methods outlined above.

Example 1

500 g of PEI-600 (PEI of 600 mol. Wt, 14 functionality) and 20.3 g ofwater are added to a clean and dry nitrogen purged autoclave to form acomposition. The composition is heated to 170-180° F. with agitation.While heating, the autoclave is evacuated to 3.7 mm Hg. A nitrogensparge through a dip tube aids mass transfer. This operation iscontinued until less than or equal to 0.2 parts by weight water, basedon the total weight of the composition, is present in the composition.Potassium borohydride is added and the composition is agitated for 2hours at 170-180° F. After cooling to <140° F., the vacuum is relievedand 90 g of water added. After agitating at 122-140° F. for 30 minutes,the composition is heated to 266° F. and the autoclave inertized with 34psig nitrogen.

The PEI in the composition is converted to PEI-20 EO, i.e., EPEIproduct, having 20 moles EO at each available site. More specifically,the composition, including 500 g of PEI along with the water andpotassium borohydride, is added to a clean, dry and nitrogen purgedautoclave along with 18 grams of 45% potassium hydroxide. Thecomposition is heated to 284-300° F. and subjected to agitation andvacuum until no more water distills off. The vacuum is released, theautoclave is padded with 34 psig nitrogen for safety reasons, and 10.3kg of ethylene oxide are charged at 284-300° F. while keeping thecomposition inerted with 34 psig nitrogen. After all ethylene oxide isin the autoclave, the composition is reacted out at 284-300° F. toconstant pressure to make the EPEI product, cooled to below 80° C.,water is added to obtain an aqueous solution including from 70 to 90parts by weight (or any other desired concentration) of the EPEIproduct, based on the total weight of the aqueous solution, and theaqueous solution is discharged. The aqueous solution of the EPEI productin water is lighter in color than the Comparative Examples, with aGardner color value of 3.0.

Example 2

49.7 kg of PEI-600 (PEI of 600 mol. Wt, 14 functionality) and 9.95 kg ofwater are added to a clean and dry nitrogen purged autoclave to form acomposition. The composition is heated to 170-180° F. with agitation.While heating, the autoclave is evacuated to 50 mm Hg. A nitrogen spargethrough a dip tube aids mass transfer. This operation is continued untilless than or equal to 0.1 parts by weight of water, based on the totalweight of the composition, is present in the composition. Potassiumborohydride is added and the composition agitated for 3 hours at170-180° F. After cooling to <140° F., the vacuum is relieved and 6.7 kgof water added. After agitating at 122-140° F. for 45 minutes, thecomposition is heated to 248-257° F. and the autoclave inertized with 34psig nitrogen.

The PEI in the composition is converted to PEI-20 EO, i.e., EPEIproduct, having 20 moles EO at each available site. More specifically, aportion of the composition, including 17.6 kg of PEI along with thewater and potassium borohydride, is added to a clean, dry and nitrogenpurged autoclave along with 0.69 kg of 45% potassium hydroxide. Thecomposition is heated to 287-300° F. and subjected to agitation andvacuum until no more water distills off. The vacuum is released, theautoclave is padded with 34 psig nitrogen for safety reasons, and 362 kgof ethylene oxide are charged at 287-300° F. while keeping thecomposition inerted with 34 psig nitrogen. After all ethylene oxide isin the autoclave, the composition is reacted out at 287-300° F. toconstant pressure to make the EPEI product, cooled to below 80° C.,water is added to obtain an aqueous solution including from 70 to 90parts by weight (or any other desired concentration) of the EPEIproduct, based on the total weight of the aqueous solution, and theaqueous solution is discharged. The aqueous solution of the EPEI productin water is lighter in color than the Comparative Examples, with aGardner color value of 3.0.

Example 3

64.3 kg of PEI-600 (PEI of 600 mol. Wt, 14 functionality) and 12.8 kg ofwater are added to a clean and dry nitrogen purged autoclave to form acomposition. The composition is heated to 170-180° F. with agitation.While heating, the autoclave is evacuated to 50 mm Hg. A nitrogen spargethrough a dip tube aids mass transfer. This operation is continued untilless than or equal to 0.1 parts by weight of water, based on the totalweight of the composition, is present in the composition. Potassiumborohydride is added and the composition agitated for 3 hours at170-180° F. After cooling to <140° F., the vacuum is relieved and 11.7kg of water added. After agitating at 122-140° F. for 45 minutes, thecomposition is heated to 248-257° F. and the autoclave inertized with 34psig nitrogen.

The PEI in the composition is converted to PEI-20 EO, i.e., EPEIproduct, having 20 moles EO at each available site. More specifically, aportion of the composition, including 17.8 kg of PEI along with thewater and potassium borohydride, is added to a clean, dry and nitrogenpurged autoclave along with 0.69 kg of 45% potassium hydroxide. Thecomposition is heated to 287-300° F. and subjected to agitation andvacuum until no more water distills off. The vacuum is released, theautoclave is padded with 34 psig nitrogen for safety reasons, and 366 kgof ethylene oxide are charged at 287-300° F. while keeping thecomposition inerted with 34 psig nitrogen. After all ethylene oxide isin the autoclave, the composition is reacted out at 142-148° C. toconstant pressure to make the EPEI product, cooled to below 80° C.,water is added to obtain an aqueous solution including from 70 to 90parts by weight (or any other desired concentration) of the EPEIproduct, based on the total weight of the aqueous solution, and theaqueous solution is discharged. The aqueous solution of the final EPEIin water is light in color with a Gardner color value of 3.0.

Comparative Example 1

259 g of PEI-600 (PEI of 600 mol. Wt, 14 functionality) are added to aclean and dry nitrogen purged autoclave together with potassiumborohydride to form a composition. The composition is heated to 174-185°F. with agitation. While heating, the autoclave is evacuated to 50 mmHg. A nitrogen sparge through a dip tube aids mass transfer. Thisoperation is continued for 5 minutes, and then the vacuum is releasedwith nitrogen. After cooling to <140° F., 49 g of water are added. Afteragitating at 122-140° F. for 15 minutes, the composition is heated to248-257° F. and the autoclave is inertized with 34 psig nitrogen.

The PEI in the composition is converted to PEI-20 EO, i.e., EPEIproduct, having 20 moles EO at each available site. More specifically,the composition, including 259 g of PEI along with the water andpotassium borohydride, is added to a clean, dry and nitrogen purgedautoclave along with 18 g of 45% potassium hydroxide. The composition isheated to 287-300° F. and subjected to agitation and vacuum until nomore water distills off. The vacuum is released, the autoclave is paddedwith 34 psig nitrogen for safety reasons, and 5.32 kg of ethylene oxideare charged at 287-300° F. while keeping the composition inerted with 34psig nitrogen. After all ethylene oxide is in the autoclave, thecomposition is reacted out at 287-300° F. to constant pressure to makethe EPEI product, cooled to below 80° C., water is added to obtain anaqueous solution including from 70 to 90 parts by weight (or any otherdesired concentration) of the EPEI product, based on the total weight ofthe aqueous solution, and the aqueous solution is discharged. Theaqueous solution of the EPEI product in water has a brownish-yellowcolor with a Gardner color value of 8.0.

Comparative Example 2

46.9 kg of PEI-600 (PEI of 600 mol. Wt, 14 functionality) are added to aclean and dry nitrogen purged autoclave to form a composition. Thecomposition is heated to 174-185° F. with agitation. While heating, theautoclave is evacuated to 50 mm Hg. A nitrogen sparge through a dip tubeaids mass transfer. This operation is continued for 15 minutes, and thenthe vacuum is released with nitrogen. Potassium borohydride is added andthe composition agitated for 2 hours at 176-185° F. After cooling to<140° F., 8.1 kg of water are added. After agitating at 122-140° F. for15 minutes, the composition is heated to 248-257° F. and the autoclaveis inertized with 34 psig nitrogen.

The PEI in the composition is converted to PEI-20 EO, i.e., EPEIproduct, having 20 moles EO at each available site. More specifically, aportion of the composition, including 21.2 kg of PEI along with thewater and potassium borohydride, is added to a clean, dry and nitrogenpurged autoclave along with 0.56 kg of 45% potassium hydroxide. Thecomposition is heated to 287-300° F. and subjected to agitation andvacuum until no more water distills off. The vacuum is released, theautoclave is padded with 34 psig nitrogen for safety reasons, and 436 kgof ethylene oxide are charged at 287-300° F. while keeping thecomposition inerted with 34 psig nitrogen. After all ethylene oxide isin the autoclave, the composition is reacted out at 287-300° F. toconstant pressure to make the EPEI product, cooled to below 80° C.,water is added to obtain an aqueous solution including from 70 to 90parts by weight (or any other desired concentration) of the EPEIproduct, based on the total weight of the aqueous solution, and theaqueous solution is discharged. The aqueous solution of the EPEI productin water has a brownish-yellow color with a Gardner color value of 15.0.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. The invention may bepracticed otherwise than as specifically described within the scope ofthe appended claims. In addition, the reference numerals in the claimsare merely for convenience and are not to be read in any way aslimiting.

1. A method of treating a composition, said method comprising the stepsof: providing the composition including impurities and a componentselected from the group of polyethyleneimine, alkoxylatedpolyethyleneimine intermediate, and combinations thereof; adding waterto the composition; and stripping the water and at least a portion ofthe impurities from the composition including the component at atemperature of from 158 to 203° F. until less than or equal to 0.2 partsby weight of water, based on the total weight of the composition, ispresent in the composition.
 2. A method as set forth in claim 1 whereinthe water is added in an amount of from 2 to 20 parts by weight based onthe total weight of the composition.
 3. A method as set forth in claim 1wherein the water is stripped at a pressure of from 0.1 to 250 mm Hg. 4.A method as set forth in claim 1 wherein the water is stripped in thepresence of a non-condensable gas sparge.
 5. A method as set forth inclaim 1 further comprising the step of agitating the compositionincluding the water during the step of stripping the water.
 6. A methodas set forth in claim 1 further comprising the step of adding aborohydride selected from the group of potassium borohydride, sodiumborohydride, and combinations thereof to the composition.
 7. A method asset forth in claim 1 wherein the polyethyleneimine in the compositionhas a number average molecular weight of at least
 150. 8. A method asset forth in claim 1 wherein the alkoxylated polyethyleneimineintermediate in the composition has a number average molecular weight ofat least
 1000. 9. A method as set forth in claim 1 wherein thecomposition is substantially free of alkoxylated polyethyleneimineintermediate.
 10. A method of making an alkoxylated polyethyleneimineproduct comprising the steps of: adding water to a composition includingimpurities and a component selected from the group of polyethyleneimine,alkoxylated polyethyleneimine intermediate, and combinations thereof;stripping the water and at least a portion of the impurities from thecomposition including the component at a temperature of from 158 to 203°F. until less than or equal to 0.2 parts by weight of water, based onthe total weight of the composition, is present in the composition; andalkoxylating the component in the composition to make the alkoxylatedpolyethyleneimine product.
 11. A method as set forth in claim 10 whereinthe water is added in an amount of from 2 to 20 parts by weight based onthe total weight of the composition.
 12. A method as set forth in claim10 wherein the water is stripped at a pressure of from 0.1 to 250 mm Hg.13. A method as set forth in claim 10 wherein the water is stripped inthe presence of a non-condensable gas sparge.
 14. A method as set forthin claim 10 further comprising the step of agitating the compositionincluding the water during the step of stripping the water.
 15. A methodas set forth in claim 10 further comprising the step of adding aborohydride to the composition.
 16. A method as set forth in claim 10wherein the polyethyleneimine has a number average molecular weight ofat least
 150. 17. A method as set forth in claim 10 where thealkoxylated polyethyleneimine intermediate has about 1 mole of alkyleneoxide for each functionality of the polyethyleneimine.
 18. A method asset forth in claim 10 further comprising the step of adding a hydroxideselected from the group of potassium hydroxide, sodium hydroxide, andcombinations thereof to the composition prior to the step ofalkoxylating and subsequent to the step of stripping the water.
 19. Amethod as set forth in claim 18 wherein the component in the compositionis alkoxylated with from 5 to 40 alkylene oxide molecules for eachfunctionality of the polyethyleneimine to make the alkoxylatedpolyethyleneimine product.
 20. A method as set forth in claim 19 furthercomprising the step of forming an aqueous solution including from 70 to90 parts by weight of the alkoxylated polyethyleneimine product based onthe total weight of the aqueous solution.
 21. A method as set forth inclaim 20 wherein the aqueous solution of the alkoxylatedpolyethyleneimine product has a Gardner color value of less than orequal to 6 as measured in accordance with ASTM D 1544-04.
 22. A methodas set forth in claim 10 further comprising the step of partiallyalkoxylating polyethyleneimine with an alkylene oxide to form thecomposition including the alkoxylated polyethyleneimine intermediate.23. A method as set forth in claim 22 where the alkoxylatedpolyethyleneimine intermediate has about 1 alkylene oxide molecule foreach functionality of the polyethyleneimine.
 24. A method as set forthin claim 22 further comprising the step of adding a hydroxide selectedfrom the group of potassium hydroxide, sodium hydroxide, andcombinations thereof to the composition prior to the step ofalkoxylating and subsequent to the step of stripping the water.
 25. Amethod as set forth in claim 24 wherein the alkoxylatedpolyethyleneimine intermediate in the composition is alkoxylated with abalance of the alkylene oxide to obtain from 5 to 40 alkylene oxidemolecules for each functionality of the polyethyleneimine to make thealkoxylated polyethyleneimine product.
 26. A method as set forth inclaim 25 further comprising the step of forming an aqueous solutionincluding from 70 to 90 parts by weight of the alkoxylatedpolyethyleneimine product based on the total weight of the aqueoussolution.
 27. A method as set forth in claim 26 wherein the alkoxylatedpolyethyleneimine product has a Gardner color value of less than orequal to 6 as measured in accordance with ASTM D 1544-04.
 28. A methodof treating a composition, said method comprising the steps of:providing the composition including impurities, water, andpolyethyleneimine; optionally, adding water to the composition to attainfrom 2 to 20 parts by weight water based on the total weight of thecomposition; and stripping the water and at least a portion of theimpurities from the composition at a temperature of from 158 to 203° F.until less than or equal to 0.2 parts by weight of water, based on thetotal weight of the composition, is present in the composition.
 29. Amethod as set forth in claim 28 wherein the composition is providedhaving from 2 to 20 parts by weight of water.
 30. A method as set forthin claim 28 wherein the water is stripped at a pressure of from 0.1 to250 mm Hg.
 31. A method as set forth in claim 28 wherein the water isstripped in the presence of a non-condensable gas sparge.
 32. A methodas set forth in claim 28 further comprising the step of agitating thecomposition including the water during the step of stripping the water.33. A method as set forth in claim 28 further comprising the step ofadding a borohydride selected from the group of potassium borohydride,sodium borohydride, and combinations thereof to the composition.
 34. Amethod as set forth in claim 28 wherein the polyethyleneimine in thecomposition has a number average molecular weight of at least 150.